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Green Hydra (Chlorohydra viridissima)

Posted: Sat Nov 02, 2019 8:36 pm
by Chris Dee
Big green from the tank. Experimenting with coloured oblique illumination.

Re: Green Hydra (Chlorohydra viridissima)

Posted: Sun Nov 03, 2019 4:33 am
by 75RR
Lovely images of a hydra - nice to see the whole creature and closeups. You are lucky to have them to hand!

Like the oblique - works well. Black and beige backgrounds look best in my opinion.

Not sure that yellow or PANTONE 572 C are ideal background colours - especially with green subject. :)

Re: Green Hydra (Chlorohydra viridissima)

Posted: Sun Nov 03, 2019 5:33 pm
by charlie g
Thanks for sharing this beautiful , and microscopically classic historic organism in your current posting, Chris. Dark field illumination of this organism works best for me. wonderful encounter you share...I hope you can keep a population of these hydras. Charlie guevara

Re: Green Hydra (Chlorohydra viridissima)

Posted: Sun Nov 03, 2019 9:07 pm
by Chris Dee
Thanks for the feedback 75RR. I agree, not the best colours for the subject, just something a little different. Pink next ;) The tank has a healthy population of green and brown Hydra, this one was rinsed back to its home.

Thanks Charlie. I've a floating ring in the tank to keep an area free of duckweed, the fringe of duckweed around this seems to be their favourite hunting spot. They've been around since I started the indoor tank in May, It'll be interesting to see how things change over winter.

Re: Green Hydra (Chlorohydra viridissima)

Posted: Sat Jan 04, 2020 5:14 pm
by Radazz
Just curious, do green hydra eat other organisms, or just photosynthesize?

Re: Green Hydra (Chlorohydra viridissima)

Posted: Sat Jan 04, 2020 7:02 pm
by MicroBob
Hi Radazz,
at minute 1 you can see how they get their food: They wait, and when an animal touches them they paralyse it and it's food.

I had them in my tank, but not now as far as I know.


Re: Green Hydra (Chlorohydra viridissima)

Posted: Mon Jan 06, 2020 3:49 pm
by mintakax
Awesome video, thank you ! I've seen two of these in my tank when it first started but nothing since. I'm curious Chris, was this a well slide ? Also I would very much appreciate to see details of you tank ? There is a lot I need to do differently on my own tank.

Re: Green Hydra (Chlorohydra viridissima)

Posted: Mon Jan 06, 2020 9:20 pm
by Chris Dee
Hi mintakax. The slide used was a standard one with cover slip, though the detritus that invariably gets included in my pipette samples does tend to elevate the cover slip. I've tried well slides and find them awkward to work with, but I imagine they may work well with larger specimens such as this. I've recently had some success collecting hydra by floating a cover slip on the surface, which minimises unwanted detritus.

The tank is nothing special. Just a cheap 10L fish tank which was populated with mud/root mass, aquatic plants, a few rocks and a piece of sunken wood. These and the water were collected from local ponds/canal. The tank uses a small bubbler which runs 12hrs on, 12 off, and sits on a north facing windowsill. I feed the tank once a week with a pinch for fishfood and top it up when needed with rainwater which has been allowed to reach room temperature. The tank has accumulated a dense surface layer of duckweed so I've added a 10cm dia' floating ring made from some 4mm tubing. This creates a duckweed-free area which is convenient for feeding and floating cover slips on the surface.

Its been interesting to watch the fauna and flora of the tank change with the diminished light in these (UK) winter months. I'm looking forward to seeing if the population of species which have declined recover without intervention in the coming spring/summer months. I recently added one of those cheap USB microscopes to the side of the tank hoping to be able to observe a small area of the tank remotely. This was a fail due to the built-in illumination causing reflections on the tank wall, some form of oblique illumination is needed I suspect to get any results. All good fun. :)

Please tell us about your tank, I'm sure we could all benefit from hearing about it.